LUDOC-276 protocol: Document RPCs for setattr

[doc/protocol.git] / ost_punch.txt

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+Command 10: OST_PUNCH
+~~~~~~~~~~~~~~~~~~~~~
+[[ost-punch-rpc]]
+
+An RPC that modifies the size attribute of a resource on an OST.
+
+.OST_PUNCH Generic Packet Structure
+image::ost-punch-generic.png["OST_PUNCH Generic Packet Structure",height=100]
+
+//////////////////////////////////////////////////////////////////////
+The ost-punch-generic.png diagram resembles this text art:
+
+       OST_PUNCH:
+      --request-------------------------------
+      | ptlrpc_body | ost_body | lustre_capa |
+      ----------------------------------------
+      --reply-------------------
+      | ptlrpc_body | ost_body |
+      --------------------------
+//////////////////////////////////////////////////////////////////////
+
+'ptlrpc_body'::
+RPC descriptor.
+
+'ost_body'::
+Metadata about the resource, as it appears on the OST.
+
+'lustre_capa'::
+So called "capabilities" structure. This is deprecated in recent
+versions of Lustre, and commonly appears in the packet header as a zero
+length buffer.
+